Conventionally, illumination apparatuses using LED (light emitting diode) elements as a light source are utilized for various home appliances, office automation equipment, vehicle display lamps, general illumination, vehicle-mounted illumination, and displays. Some illumination apparatuses include a semiconductor device having an LED substrate and an LED element.
Examples of the LED element include those that emit light in a visible region typically represented by red, green, and blue and an ultraviolet region. Since a wavelength distribution of the light emitted from these light emitting elements is basically narrow, it can be said that the light can be seen as a single color in appearance. Examples of white LED put to practical use include those synthesizing white color by using an LED element emitting light at a high energy such as an ultraviolet or a blue color and a fluorescent material converting a portion of the light into light of a longer wavelength, or those synthesizing a white color by using elements of plurality of colors.
As the semiconductor device described above, Patent literature 1 describes, for example, those in which a concave portion is formed on one surface of a Cu substrate, an LED element is mounted on the concave portion, Cu interconnect layer for connection is formed over an insulating layer disposed on the side of the concave portion, a terminal portion of the LED and the Cu interconnect layer are connected each other by a wire bonding, and the terminal portion and the Cu interconnected layer are resin-encapsulated. Further, in the Patent literature 1, Ag plating is applied to the surface of the Cu interconnect layer.